Hydrodynamic clutch and method for influencing the torque that can be picked up by the hydrodynamic clutch

ABSTRACT

The invention relates to a hydrodynamic clutch which comprises a primary impeller and a secondary impeller which together define a working chamber. The clutch also comprises means for influencing the transmission behavior of the hydrodynamic clutch, especially for influencing the circulation flow in the working chamber, said means comprising at least one baffle plate that extends at least partially into the working chamber. The inventive clutch is characterized in that the baffle plate can be displaced in the axial direction relative to the working chamber.

The present application is a U.S. National Application ofPCT/EP2004/012701 (the “Application”), filed Nov. 10, 2004, by VoithTurbo GmbH & Co. KG, which claims priority to German application number10353517.9, filed Nov. 14, 2003, the contents of which are hereinincorporated by reference.

The invention relates to a hydrodynamic clutch with the characteristicsin detailed in the preamble of claim 1; and additionally a method forinfluencing the torque that can be picked up by the hydrodynamic clutch.

BACKGROUND

From the state of the art, hydrodynamic clutches in start-up units forvehicles are known in a multitude of implementations. The start-up unitcomprises thereby a drive that can be coupled to an input and an outputthat can be coupled to a power take-off. The hydrodynamic clutch whichcomprises a primary impeller and a secondary impeller, that togetherform a toroidal working chamber, is arranged between the input and theoutput. The primary impeller is thereby, for example, provided with aso-called primary impeller cup that is torque proof connected to it, andthat encloses the secondary impeller in the axial direction, andcompletely in the circumferential direction. In addition, the start-upunit comprises a controllable clutch in the form of a direct-driveclutch that is arranged parallel to the hydrodynamic components, inparticular the clutch, and that can be controlled together with it or onits own. This means that through both clutches two power branches arecreated, whereby the power flux either takes place only through one ofthe clutches, or collectively through both. The controllable clutchcomprises thereby at least a clutch input element and a clutch outputelement, whereby the clutch output element is coupled, at leastindirectly torque proof, to the secondary impeller. The input clutchelement is connected, at least indirectly torque proof, with the primaryimpeller and/or the input. The means for the creation of a frictionalcontact between the individual clutch elements comprise thereby a pistonelement that can be impacted upon by a pressure medium. It can bearranged separately from the clutch disks or else formed directly on thesecondary impeller in particularly compact implementations. Thehydrodynamic clutch is in addition provided with a utilities supplysystem. The clutch can thereby be flowed through centrifugally andcentripetally. In the case of centripetal flow-through, the utilitiesare led, via the utilities supply channel, along the outer circumferenceof the secondary impeller and injected into it in the radial directionin the region of the outer circumference of the toroidal workingchamber. The force created by the utilities is thereby utilized to keepthe controllable clutch in a relaxed state or to operate with at least acertain amount of slippage, respectively. The exit from the toroidalshaped working chamber thereby takes place in the region of the radialinner diameter of the working chamber in a space that lies thereunderand which is also designated as a second utilities guide channel orchamber. The first utilities channel and/or chamber, that is restrictedby the inner circumference of the casing and the outer diameter of thesecondary impeller, as well as the second utilities supply channeland/or chamber can thereby be interchanged as regards their function.This is necessary in particular during the change over from centripetalto centrifugal flow-through. The supply of the utilities for thehydrodynamic coupling takes place via the second utilities supplychannel and/or chamber in the region of the radial inner diameter of theworking chamber, whereby the exit takes place in the region of theradial outer diameter of the working chamber on one of the impellers orbetween both. The controllable clutch is then activated. In suchstart-up units the performance ratio can thus be varied via theindividual clutches—controllable clutch or hydrodynamic clutch. It isthereby in particular during the operation of the hydrodynamic clutchdesirable that, for the avoidance of a negative retroaction on thenumber of revolutions of the driving machine, the torque that can bepicked-up by the hydrodynamic clutch and that corresponds to the torquethat can be picked-up by the primary impeller, is kept as low aspossible. This is attempted by adjustment of a minimal fill factor.However, it has become clear that this measure only is insufficientsince exactly in the range of very high coupling slippage, for exampleof 70 to 100 percent, torques that are too high are still picked-up bythe clutch. It can lead therefore to an undesirable retroaction in theform of suppression of the number of revolutions of the driving machinethat is coupled to the hydrodynamic clutch, so that then the desireddriving dynamics is no longer present.

SUMMARY

The invention therefore had as a basis the task to create a hydrodynamicclutch of the kinf mentioned in the introduction for the application ofstart-up units in which, with the smallest constructive and controltechnical complexity, a minimal idle torque, i.e. in particular of the,via the hydrodynamic clutch, at maximum slippage absorbable torque inthe start-up and/or start region, can be attained.

The solution according to the invention is characterized by the featuresof claim 1. Advantageous embodiments are represented in the sub claims.

According to the invention, a hydrodynamic clutch which comprises atleast a primary impeller and a secondary impeller, is provided withmeans for the influencing of the transmission, in particular means forthe influencing of the circulation flow in the working chamber, whichcomprise, at least, an element that forms an interference and/or baffleregion, in particular baffle plates that extend at least partially intothe working chamber and that according to the invention can be displacedin the axial direction, i.e. parallel to the rotation axis of thehydrodynamic clutch, in the working chamber. By the interference and/orthe baffle region, a region is meant that, viewed in cross section ofthe theoretical progression and/or direction of the circulation flow,briefly deflects at least over a sub range in the circumferentialdirection. The deflection, i.e. direction change, takes place therebytoward the direction of the central diameter of the working chamberand/or the core chamber. The available flow cross section tapers in theregion characterized by the baffle region. The interference and/orbaffle region is thereby arranged in such a way that it is characterizedby at least one interference surface which is constructed eitherperpendicular, or at an angle, to the flow progression of thecirculation flow in a work cycle in this range, and which stretches,preferably completely in the circumferential direction, over at least apart of the region of the working chamber.

The element that forms the interference or baffle region is preferablyarranged in the shape of a washer, whereby the cross section can bearranged arbitrarily. The restricting effect takes thereby place in thecircumferential direction over the total circumference in the workingchamber. Embodiments of elements are conceivable that form aninterference or baffle region in the form of a partly ring shapedelement or segment.

The solution according to the invention allows for a freely variableinfluencing of the transmission of the hydrodynamic clutch dependent onthe freely chosen position of an element that forms the interference orbaffle region, in particular the baffle plate in the working chamber,during each operation phase, and thereby of its effect on thecirculation flow which establishes itself in the working chamber.According to. the position of the element that forms the interference orbaffle region, in particular the baffle plate and the arrangement of theinterference and/or baffle region formed by these in the workingchamber, the transmission of the hydrodynamic clutch can be influencedin a controlled way at a certain slippage by a change of the position ofthe element that forms the interference or baffle region and themagnitude of the provided displacement as well as the displacement speedover a slippage region. The element that forms the interference orbaffle region, in particular the baffle plate, is in the startingposition, i.e. at rest, located in the region of the parting planebetween the two impellers. During a decrease of the slippage, adisplacement over the axial extension of the respective impeller takesplace in axial direction away from the center and/or the core chamber ofthe working chamber. The influence of the baffle plate, in particular aninterference and/or active surface which acts on the circulation flowthrough it, can thereby be adjusted in a targeted way over the totaloperation range of the hydrodynamic clutch, preferably over the totalslippage range. It is thereby possible to influence the transmission ofthe hydrodynamic clutch also over a wider range up to the totaloperation range. This influencing is characterized at least as afunction of the axial position of the baffle plate and the geometricdimensions of the baffle plate. The change of the action of the baffleplate arises then dependent on the change of the position of the baffleplate in axial direction via the slippage.

In order to achieve the desired performance curve characteristics, themeans for the influencing of the circulation flow constitute either atleast an external or an internal interference and/or baffle region inthe working chamber. Preferably, it is assigned one of the twoimpellers. According to the construction and implementation, the baffleplate is constructed in such a way that it forms, in relation to theworking chamber, either an external baffle or an internal baffle. In thecase of a construction as an external baffle, the element that forms theinterference or baffle region, in particular the baffle plate, isarranged in the region of the radial external dimensions of the workingchamber, while in the case of an implementation as an internal baffle,the element that forms the interference or baffle region, in particularthe baffle plate, extends inside the working chamber from the its innerdiameter in the radial direction. However, preferably a placement ischosen which lies in the region of the inner diameter of the workingchamber, whereby in this case an especially compact construction of thehydrodynamic clutch with the accompanying control equipment for theelement that forms the interference and/or baffle region, in particularthe baffle plate, can be realized.

The element that forms the interference or baffle region, in particularthe baffle plate, is preferably always assigned one of the impellers.The assignment can thereby take place for the primary impeller as wellas for the secondary impeller. The effect is dependent on the assignmentof the same. The displacement takes place thereby, starting from theregion of the parting plane, or a region that is adjacent to it, over atleast a part, preferably the total axial extension of the partconstructed from the respective impeller, of the working chamber. Thatis, the displacement takes place in the axial direction away from thegeometrical center of the working chamber and the core chamber,respectively.

The element that forms the interference or baffle region, in particularthe baffle plate, can thereby be constructed as a separate component butcan also constitute with a part of this impeller a structural unit,i.e., it can be constructed as a one-piece component, constituent of oneof the impellers. The baffle plate can in the first case be

-   -   a) on the respective impeller or    -   b) an element connected to it torque proof or    -   c) a stationary component or casing or    -   d) an element assigned to the baffle plate which rotates with a        relative rotational speed with respect to the impeller.

The element that forms the interference or baffle region, in particularthe baffle plate, according to the implementation as an external baffleor an internal baffle, is in case a) provided in the region of its innerdiameter or its outer diameter with slits, whereby the slits extend inthe axial direction—in case of slantwise blading at least with onedirection component in the circumferential direction—and serve to absorbthe baffles of the blading that are used for guidance. The guidance ofthe baffle plate then takes place at the blading whereby the blading inthe guiding region is free from a linkage to the part that carries thebaffle. This means that in this region the working chamber is notrestricted by the internal contour of the part that carries the blade,but projects freely over the blades in the radial direction. The guidingslits are thereby to be adjusted to the blading, whereby the slits,according to implementation of the blading, is constructed as straightor slanted blading. In case of the guidance of the baffle plate on arespective impeller, a uniform rotation speed between the element thatsupports the baffle plate and the respective impeller must always beensured. In essence, for the implementation of the guiding slits and theaxial movability of the baffle plate in the case of slanted blading, thefollowing possibilities exist:

-   a) the element that forms the baffle plate and/or the interference    or baffle region, is led for a change in position in the axial    direction in the circumferential direction along the slantwise    oriented blading, or-   b) the guiding slits are constructed with such a width in the    circumferential direction that also in the case of a slanted blading    a pure axial displacement, without a rotation, of a certain    magnitude in the circumferential direction is possible.

According to a particularly advantageous embodiment, in which theguiding of the element that forms an interference or baffle region, inparticular the baffle plate, can take place independently from theimplementation of the hydrodynamic clutch, in particular of the bladecarrying parts and on other components according to c) and d), ischaracterized by that the respective impeller, viewed in cross section,is in the radial direction correspondingly turned away. A ring-shapedelement is thereby abraded with respect to the blading either in theregion of the external circumference or in the region of the internalcircumference, whereby the blading, viewed in cross section, ischaracterized by blade sides and/or blade ends that are constructed inradial direction parallel to the rotation axis. This means that thering-shaped turning-away extends over the total axial extension of therespective impeller or at least a part of the region of certainmagnitude which corresponds at least to the sum of the displacement andthe width of the baffle plate. The baffle plate can then be displaced inthe region of the parting plane over the total extension and even beyondit relative to the respective impeller, whereby the baffle plate can besupported also by a stationary element or an element which rotates witha relative rotation speed with respect to the respective impeller, andwhich can be guided on it displaceable in the axial direction.

In the other case, i.e. in the case of a structural unit with cycleleading wall regions, the baffle plate is a component of a wall region,preferably a section of the blade carrying part of one of the twoimpellers. In this case a displacement of the baffle plate in axialdirection can only take place via a displacement of the cycle leadingsection of the blade carrying part of the respective impeller. This isrealized by that, viewed in cross section of the hydrodynamic component,a segment of an impeller can be displaced in the axial direction. Thissegment involves thereby a region in the region of the radial externaldimensions of the working chamber or in the region of the radialinternal dimensions of the working chamber that lies in a sub region ofthe respective impeller. The guidance thereby takes place coaxially withthe hydrodynamic component, in particular the respective impeller. Themagnitude of the displacement can be fixed according to the constructionand the choice of the segment on the respective impeller. Thedisplacement can thereby take place up to a concise seal with the bladecarrying part, or else up to the point that the blade carrying partforms a limit stop for the displacement of the baffle plate and therebythe segment in axial direction of the impeller.

With respect to the construction of the baffle plate itself a pluralityof possibilities exists. In the simplest case it is constructed as awasher shaped element comprising two parallel to each other oriented andactive-surface-forming front sides, whereby the front sides, seen in theassembly position, extend perpendicular to the rotation axis. Accordingto a particular advantageous construction, the contour, in particularthe active surface which is constructed on the baffle plate, can beconstructed with a geometrical shape and contour in such a way that ithas additional advantageous properties with respect to the guidance ofthe circulation flow. Preferably, shapes for the active surfaces arethereby chosen of which each in the flow direction extends, rising inthe flow direction, into the working chamber from the region of theexternal diameter and/or the internal diameter. This means that theactive surface is not constructed as a purely perpendicular orientedsurface with respect to the circulation flow but allows a guidance ofthe circulation flow along it in all states of operation, whereby thereversal and/or direction change takes place gradually. The contour ispreferably chosen in such a way that it, when fully displaced withrespect to the respective impeller, is modeled in this setting on thegeometry of the internal contour of the blade carrying region andthereby the blade bottom. In this case influencing is no longer createdout in the state in which an influencing is no longer desired, since thebaffle plate takes over the function of the missing blade carryingsection.

The element that forms the interference or baffle region, in particularthe baffle plate, is assigned a control unit for the realization of thedisplacement. This unit can be constructed in an arbitrary manner andcan be driven mechanically, hydraulically, pneumatically, electrically,or by a combination of these possibilities.

Preferably, hydraulic or pneumatic solutions are chosen. Thedisplacement then results, for example, from the, at least indirect,connection of the element that forms the interference or baffle region,in particular the baffle plate, to a cylinder-/piston unit, whereby theactuation of the piston can take place with pressure from an arbitrarypressure source. The actuation pressure can thereby be built from, forexample,

-   -   a) a pressure that corresponds to the pressure in the supply        channel or chamber or one proportional to this pressure at hand,        or    -   b) the pressure inside the casing    -   c) an overpressure from a) and b), or    -   d) a pressure that is freely chosen, or    -   e) an arbitrary pressure that is in any case available in the        power train, for example, transmission pressure, etc.    -   f) an overpressure from one of the in a) to c) mentioned        pressures and a pressure according to d) or e).

The solution according to the invention is appropriate for any type ofhydrodynamic clutch. It can thereby involve hydrodynamic clutches withrotating casing, i.e., with a primary impeller cup that is attachedtorque proof with the primary impeller as well as hydrodynamic clutcheswith casing that is stationary, i.e., at rest. In addition, the solutionaccording to the invention can be employed in particular in start-upunits which comprise a start-up element in the form of a hydrodynamicclutch with an assigned device for the bridging in the form of adirect-drive clutch. In this case, the direct-drive clutch is preferablyconstructed as a disk clutch and arranged parallel to the hydrodynamicclutch. The hydrodynamic clutch is assigned a utilities supply systemand/or guidance system that allows for a centrifugal and centripetalflow through the hydrodynamic clutch. In the case of centripetal flowthrough, thereby at least a part of the, around the externalcircumference of the hydrodynamic clutch guided, and in the region ofthe external circumference in the parting plane inserted, utilities forthe actuation of the direct-drive clutch. These utilities aredeactivated by the pressure available to the direct-drive clutch in thisoperation state, i.e., the elements that can be brought into activefrictional engagement are kept at a distance from each other.

In the case of centrifugal flow through the utilities supply takes placein the region of the internal diameter of the toroidal working chamberand the flow through takes place in the centrifugal direction, i.e.,outwards from the region of the external circumference of thehydrodynamic clutch. The unit consisting of a hydrodynamic clutch anddirect-drive clutch is thereby provided with a first utilities supplychannel or chamber which is at least constructed between the controlequipment of the direct-drive clutch and a casing that encloses theunit. In addition, a second utilities supply channel or chamber isprovided which is arranged in the region of the external circumferenceon the internal diameter of the toroidal working chamber. The assignmentin the case of chambers can be specified according to choice as a supplychannel or supply chamber or removal channel or removal chamber to orfrom the working chamber. This is realized via a corresponding controlequipment in the utilities supply and/or guidance system, whereby theseare preferably constructed in the form of valve devices. According tothe choice of the controlled value of the control unit assigned to the,in axial direction slidable, baffle plate, then also the pressures thatare available in the utilities supply channels or chambers can beemployed for actuation.

According to a particular advantageous implementation, the hydrodynamicclutch, in particular the blading, is constructed with a core ring. Thismeans that the blading in the core chamber is provided with a recess onevery other impeller, in particular on the ends that point to theturbine wheel, which, viewed for the total blading, describes acorresponding cavity. In addition, the blading can be varied on bothimpellers. The secondary impeller is preferably bladed slantwise. Inanalogy, this applies also to the blading in the exit region from theprimary impeller. It thereby becomes possible to achieve betterλ-values. On the other hand, the blading is constructed straight in theregion of the intake at the primary impeller in order to make here arectilinear displacement of the baffle plate possible in the arrangementin the region of the inner diameter of the working chamber.

In analogy, this also applies in the reverse to the arrangement of thebaffle plate in the region of the external diameter of the workingchamber, whereby then the slanted blading follows the pump intake.However, preferably the first variant is chosen. This means that anindividual blade on the primary impeller does not proceed rectilinearlyor at an angle with respect to the radial direction, but includes afirst sub region that proceeds in the radial direction and a second subregion that proceeds at an angle with respect to the radial direction.

BRIEF DESCRIPTION OF THE DRAWINGS

The solution according to the invention is clarified in the followingwith the aid of figures. In these the following is depicted in detail:

FIG. 1 demonstrates in a schematically simplified representation thebasic principle and the basic construction of a hydrodynamic clutchconfigured according to the invention with an axially displaceablebaffle plate;

FIGS. 2 a and 2 b demonstrate a construction with guidance of the baffleplate at the blading;

FIGS. 3 a to 3 c demonstrate additional possible arrangements of thebaffle plate;

FIGS. 4 a and 4 b demonstrate particular advantageous constructions withexternal and internal baffle;

FIG. 5 shows a particular advantageous construction of a hydrodynamicclutch with baffle plate;

FIG. 6 a demonstrates an application in a clutch with rotating casing;

FIG. 6 b shows an implementation with a stationary casing;

FIG. 6 c shows a possible implementation with the control unit assignedto the baffle plate;

FIG. 7 demonstrates with the aid of performance curves the operationmode of the baffle plate in different positions.

DETAILED DESCRIPTION

FIG. 1 demonstrates in a schematically very simplified representationthe basic construction and the basic principle of a hydrodynamic clutch1 configured according to the invention which comprises at least aprimary impeller 2 and a secondary impeller 3, which together form aworking chamber 4, with a, coaxially with respect to the clutch 1arranged, and in the axial direction displaceable, element that forms abaffle region or interference region, in particular in the form of abaffle plate 5. In this implementation, the baffle plate 5 is assignedthe primary impeller 2 which can be coupled to a drive. The baffle plateis thereby constructed in the shape of a washer. It extends with itsactive surface into the working chamber 4 in the radial direction. Thearrangement of the baffle plate 5, depicted in FIG. 1, involves aso-called external baffle 6. It is characterized by that it becomesactive in the region of the radial external diameter d_(A4) of theworking chamber 4. The baffle plate 5 can thereby be displaced in theaxial direction, i.e., parallel to the rotation axis R of thehydrodynamic clutch 1. Viewed from the startup procedure of the clutch1, the displacement thereby takes place starting from a region in theregion of the parting plane T over at least a sub region of the axialextension of the respective impeller, here of the primary impeller 2.The axial displacement can thereby take place only over a sub region ofthe extension of the respective impeller, here of the primary impeller2, or else preferably completely beyond the total impeller 2. In theimplementation represented in FIG. 1, the baffle plate 5 is a componentof a wall region 7 of the blade carrying part 8 of the respectiveimpeller, here of the primary impeller 2, whereby this wall region 7 isprovided in essence in the region of the external diameter d_(A2) of theprimary impeller 2 and this wall region 7 can be displaced in the axialdirection contrary to the remaining not displaceable blade carrying part8.

According to the location of the wall region 7, also a displacement ofthe baffle plate 5 results as a consequence of the forced coupling. Thebaffle plate 5 is in this case characterized by an internal diameter d₅which is smaller than the diameter d_(A4) that determines the externaldiameter of the working chamber 4, but larger than the internal diameterd₄ of the working chamber 4 in the region of the parting plane T. Theexternal diameter d_(A5) of the baffle plate 5 corresponds in this caseto the external diameter d_(A4) of the working chamber 4 or, in theconcrete case of the primary impeller 2, the internal diameter d_(i7-2)of the primary impeller, which is characterized by the internal diameterwhich characterizes the wall region 7 in the radial external region ofthe primary impeller 2. This diameter involves thereby the differencebetween the theoretical external diameter d_(A2) of the primary impellerand the wall thickness S7 of the wall region 7. As an example, thebaffle plate 5 is in the depicted case constructed as a flat disk. Itcomprises two front sides 11 and 12, each of which forming a flat frontsurface 9 and 10, whereby each of the front surfaces 9 is directed awayfrom the parting plane T at the front side 12, and points in thedisplacement direction in relation to the initial position of the baffleplate 5 at the beginning and possibly during the starting procedure. Thefront surface 10 represents thereby at least partly, in the representedcase completely, the active and/or influencing surface 20 for thecirculation flow in the working chamber 4. The wall region 7 of theblade carrying part 8 is thereby displaceable in the implementationrepresented in FIG. 1. Connected to these, also the blade region 13 ofthe blades 14 that is attached to it, can be constructed such that itcan be displaced along it. The blades 14 are then subdivided. The bladecarrying part 8 and/or the wall region 7 of the blade carrying part 8with the connected blade region 13 is thereby as well constructed in theshape of a ring. However, both are torque proof coupled to each otherand implemented displaceably relative to each other. This implementationguarantees complete displaceability in relation to the remaining bladecarrying part 8 in the axial direction, independent of the magnitude ofthe displacement I in the axial direction that is provided for theoperation mode.

However, as is not shown in FIG. 1, also the displacement of only thewall region 7 without coupling to the blade region 13 is conceivable.The wall region 7 is in this case only used for the flow guidance anddoes not primarily serve for the position fixation and attachment of theblades 14. This takes place through the remaining blade carrying region8.

Contrary to this, FIGS. 2 a and 2 b demonstrate with the aid of twoviews an alternative arrangement of an implementation of a hydrodynamicclutch 1.2 with an axially displaceable baffle plate 5.2. The latter isconstructed in this case as a separate component and displaceable in theaxial direction opposite the impeller, here, for example, the primaryimpeller 2.2, in such a sway that a change of the active surface in theworking chamber 4.2 arises through the displacement. The baffle plate5.2 is in this case also constructed as an external baffle 6.2. That is,it is arranged in the external region of the working chamber 4.2 and issupported in it. The flow is thereby reversed in this region around thebaffle and/or the baffle plate 5.2 before it overflows into thesecondary impeller 3.2. In this implementation the blades 14.2 arearranged in such a way that they project into the radial external regionof the primary impeller 2.2 over the blade carrying part 8.2, i.e., theyare guided only over a part of their extension in the radial directionat the blade carrying part 8.2 and that the radial external region ofthe primary impeller 2.2 is free from the in figure 1 represented wallregion 7.2. The baffle plate 5.2 is in this case constructed with slitsand is guided at the individual blades 14.2 that are arranged in thecircumferential direction at a distance to each other. These arepreferably directed straight, i.e., the individual blade 14.2 inarranged in a plane which is characterized by a vertical theoreticalrotation axis and the rotation axis. The axially displaceable baffleplate 5.2 is thereby guided in a region of the blade 14.2, here inparticular a freely projecting blade region 13.2, which is free from adirect guidance on the blade carrying part 8.2 and is fixated in itsposition only by the other baffle regions in the blade carrying part8.2. Implementations with slanted blading are likewise conceivable butthen the guiding slits are to be designed with a corresponding width orthe axial displacement is to be secured by twisting in thecircumferential direction. According to the magnitude of the bladeregion 13.2 and/or the blade carrying part 8.2, the displacement in anaxial direction can be guaranteed by individual guidance of the baffleplate 5.2 on the blading 14.2. An optimal displacement of the baffleplate 5.2 can be achieved in the case that the end region of the bladingcarrying region 8.2 lies in a plane that is perpendicular to a planethat is characterized by a perpendicular to the rotation axis and aperpendicular in the vertical direction and/or extends parallel to theparting plane T between the primary impeller 2.2 and secondary impeller3.2. According to the arrangement of its internal diameter d_(i5.2) thiscan take place either up to the region outside the impeller, here theprimary impeller 2.2, or at least up to the region of the blade carryingpart 8.2. If in the represented case the internal diameter d_(i5.2) isequal or preferably larger than the external diameter d_(A8) of theblade carrying part 8.2, then a concise displacement to the bladecarrying part 8.2 can take place in the axial direction or evencompletely over the blade carrying part 8.2 out of the working chamber4.2. However, this is not aimed at since then it is no longer possibleto guide the baffle plate 5.2 without additional accessories.Preferably, implementations are thereby aimed at in which a displacementtakes place as far as possible in the direction of the blade carryingpart 8.2 and/or the inner wall that is formed by it. A concisetermination and/or a stop function of the blade carrying part 8.2 ispreferably aimed at.

In FIG. 2 b an implementation is thereto represented, in a view from theright, of the baffle plate 5.2 provided with slits and/or guidings 16relevant to the guidance at the individual blades 14.2 at the internaldiameter d_(i5.2). This implementation of the baffle plate 5.2 poses apossible implementation. However, the implementation according to theinvention is not focused on this. The geometry of the slits 16 isadapted to the geometry of the blades 14.2.

FIGS. 3 a to 3 c demonstrate, in a schematically very simplifiedrepresentation with the aid of a very simplified representedhydrodynamic clutch 1.3, additional arrangement possibilities of abaffle plate 5.3 that is, according to the invention, constructed asaxially displaceable.

With respect to the connection and guidance of the baffle plate 5.3, thein FIGS. 1 and 2 described arrangement possibilities apply, but nolimitation to these ensues thereby. In this connection representativereference can be made to these figures. The baffle plate 5.3 a isassigned to the secondary impeller 3.3 a in the implementationrepresented in FIG. 3 a. The baffle plate 5.3 a is here also constructedas an external baffle 6.3 a and becomes active in the external radialregion of the working chamber 4.3 a, for example, at the secondaryimpeller 3.3 a. The baffle plate 5.3 a is also here preferablyconstructed as a washer. It can either be constructed in one piece witha wall region 7.3 a or else, as described in FIG. 2 a, can be guided inan analogous construction method on the blading 14.3 a of the secondaryimpeller 3.3 a. Concerning the external and internal diameter, theimplementations carried out for the arrangement of the primary impeller2.2 a apply.

FIGS. 3 b and 3 c demonstrate in a schematically very simplifiedrepresentation possibilities for the arrangement of an axiallydisplaceable baffle plates 5.3 b and 5.3 c as internal baffle 17.3 b and17.3 c, whereby the baffle plates 5.3 b and 5.3 c are each arranged inthe region of the radial internal dimensions of the hydrodynamic clutch1.3 b, 1.3 c, in particular of the working chamber 4.3 b and 4.3 c,respectively. The construction of the baffle plates 5.3 b and 5.3 c isalways characterized by that its external diameter d_(A5.3b),respectively, d_(A5.3c), is always larger than the internal diameterd_(i4.3) b, respectively, d_(i4.3c), of the working chamber 4.3 b,respectively, 4.3 c, as well as especially d_(2.3b) or d_(2.3) c,respectively, d_(i3.3b) or d_(i3.3c), and smaller than the internaldiameter d_(i4.3b), respectively, d_(i4.3c), of the working chamber 4.3b, 4.3 c and/or of the internal diameter, which is determined by theimpellers 2.3 b, 2.3 c and 3.3 b, 3.3 c, in the external region of thehydrodynamic clutch 1.3 b and 1.3 c. The baffle plates 5.3 b and 5.3 cextend therefore at least partly in the radial direction into theworking chamber 4.3 b and 4.3 c, respectively. As an example, FIG. 3 bdemonstrates thereby an arrangement of the baffle plate 5.3 b on theprimary impeller 2.3 b, whereby the arrangement is characterized in theregion of the internal diameter of the sub region of the working chamber4.3 b that is determined by the primary impeller 3.3 b. The baffle plate5.3 b and the wall region 7.3 b in this implementation constitutethereby, for example, a structural unit, whereby the wall region 7.3 bof the blade carrying part 8.3 b is displaceable.

The displaceability is here also in the axial direction. On the otherhand, FIG. 3 c demonstrates an implementation according to FIG. 2 withan arrangement for the secondary impeller 3.3 c, in which the baffleplate is constructed with slits 18 arranged on the externalcircumference, which is led into the blade region 13.3 c, which is freefrom a guidance on the blade carrying part 8.3 c.

According to a particularly advantageous arrangement 1.4 a, theimpeller, according to FIG. 4 a, which leads the circulation in the formof the primary impeller 2.4 a, or, according to FIG. 4 b, the secondaryimpeller 3.4 b, is constructed such a way that it is implemented to beturned away in the region of the guidance for the baffle plates 5.4 a,5.4 b. This means that the impeller, viewed in cross section, is freefrom an impeller segment 19 that is provided either in the radialexternal region of the impellers 2.4 a, 3.4 d, or else, dependent on thearrangement of the baffle plates 5.4 a, 5.4 b, in the radial internalregion. In addition, the impeller 2.4 a, 3.4 b is in this region, inparticular the blading, preferably turned away. This turning away ischaracterized by that the blade 14.4 a, 14.4 b, viewed in cross-section,is characterized by a straight edge in the radial direction either inthe region of the radial external diameter d_(A2), d_(A3), or in theregion of the radial internal diameter d_(I2), d_(I3), of the workingchamber 4.4 a, 4.4 b and/or the blading 14.4 a, 14.4 b, and that in thisregion no guiding of the circulation flow takes place. According to theinvention, the baffle plate 5.4 a, 5.4 b, respectively, is arranged inthe region, that now is left out by the turning-away, and which istheoretically filled by the blading in the normal case, according toFIG. 4 a in the region of the radial external diameter d_(A3) of thesecondary impeller 3.4 a, and according to FIG. 4 b in the region of theradial internal diameter d_(I2) of the primary impeller 2.4 b. Thebaffle plate 5.4 a, 5.4 b, can be displaced therefore unhinderedopposite the impeller 2.4, whereby the displacement can take placearbitrarily. Furthermore, this possibility offers the advantage that thebaffle plate 5.4 a, 5.4 b, no longer has to be guided on the impelleritself—primary impeller 2.4 b or for the secondary impeller 3.4 a—butcan also be guided on an element that rotates with respect to it with arelative rotational speed.

Also a guidance on a stationary component, such as, for example, thehere only implied casing 21, is conceivable.

FIG. 5 demonstrates an additional advantageous arrangement of ahydrodynamic clutch, seen in cross-section in a schematically verysimplified representation, with a baffle plate 5.5 which is according tothe invention implemented to be axially displaceable. In the representedcase, seen in cross-section, it is provided with a profile 22. Theprofile 22 is thereby implemented in such a way that it forms a guidingsurface 20.5 for the flow of the circulation flow, whereby this surfaceextends unevenly parallel to the parting plane T. A contour that risesup to the center of the working chamber is preferably chosen. This meansthat the circulation flow on the baffle plate 5.5 is deflected accordingto the geometry and the progression of the guiding surface 20.5. Thisbaffle plate 5.5 is also displaceable in the axial direction and makesit in a corresponding arrangement possible that, in a situation of a notdesired influencing, a guiding surface flush with the remaining bladecarrying part 8.5 and which, without the direction change that followsthe circulation flow in relation to the theoretical progression, followsthe blade carrying part 8.5, and normally describes the internal contourof the impeller 2.5 or 3.5—according to the assignment to the primaryimpeller or the secondary impeller. The blading 14.5 is provided, in theregion of the blade ends 23 which point to the blading of the otherimpellers, here of the secondary wheel 3.5, with a recess under theformation of a core chamber 19.

Furthermore, the blading 14.5 of the primary wheel 2.5 is constructedover its radial extension with regions of different directions. Theregion of each blade 14 of the blading 14.5 that guides the baffle plate5.5 in the represented case is thereby constructed straight and the partthat extends in the radial direction outside the region that guides thebaffle plate 5.5 is thereby constructed inclined in relation to a planethat extends perpendicular to the parting plane T.

FIGS. 6 a and 6 b demonstrate in a schematically very simplifiedrepresentation possible applications of the clutch 1 according to theinvention.

It can be implemented according to FIG. 6 a with a rotating casing 21 inthe form of a primary impeller cup 24 or, according to FIG. 6 b, it canenclosed by a stationary casing 25. A guidance of the element that formsa baffle or interference location can, according to the arrangement ofthe clutch 1 and the blading 14, also take place on the casing 21 and/or25.

FIG. 6 c demonstrates with the aid of an implementation according toFIG. 3 c a possible arrangement with a control unit 26. This is, forexample, constructed as a cylinder-/piston unit. The actuation of thepiston 18 that is coupled to the baffle plate 6.6 takes thereby place,for example, with a differential pressure that is formed from the casinginner space 29 and a control pressure.

As an example, FIG. 7 demonstrates with the aid of a ny(v)-λ-diagram theoperation mode of the element 5, which forms the interference and baffleregion, plotted in different positions over the rotational speed ratio.This shows that precisely in the startup region, i.e., at very highslippage, in relation to the known implementations from the state of theart, substantially smaller torques are picked-up because of the actionof the baffle plate 5 in the region of the parting plane T. At very lowslippage, i.e., a thereto proportional rotational speed ratio ny(v) inthe range of 1 during the ensuing displacement of the baffle plate 5still outside the working chamber and/or in a position in which it doesno longer affects an interference of the circulation flow, the effect ofthe baffle plate is not detectable.

In general the displacement of the baffle plate preferably takes placeevery time starting from the region of the parting plane between theimpellers over at least a sub region of the axial extension of therespective impeller, i.e., a part of the working chamber, preferablyoutside it. However, displaceability over a part of the axial extensionof both impellers would also be conceivable, whereby the surrounding, inparticular the mounting and/or the guiding of the baffle plate, would beadapted correspondingly.

SYMBOL REFERENCE LIST

-   1, 1.2, 1.3 a,-   1.3 b, 1.3 c,-   1.4 a, 1.4 b hydrodynamic clutch-   2, 2.2, 2.3 a-   2.3 b, 2.3 c,-   2.4, 2.4 a, 2.4 b primary impeller-   3, 3.2, 3.3 a,-   3.3 b, 3.3 c, 3.4,-   3.4 a, 3.4 b secondary impeller-   4,4.2,4.3 a,-   4.3 b, 4.3 c,-   4.4, 4.4 a, 4.4 b working chamber-   5, 5.2, 5.3 a-   5.3 b, 5.3 c, 5.4 a-   5.4 b, 5.5 baffle plate-   6, 6.2, 6.3 a external baffle-   7,7.2 wall region-   8,8.2 blade carrying part-   9 front surface-   10 front surface-   11 front side-   12 front side-   13 blade region-   14 Blade-   16 slit-   17.3 b,17.3 c internal baffle-   18 slit-   19 core chamber-   20 active and/or influencing surface-   21 casing-   22 profile-   23 blade end-   24 primary impeller cup-   25 stationary casing-   26 control unit-   27 cylinder-/piston unit-   28 piston-   29 casing inner chamber-   I displacement-   S₇ wall thickness-   a sub region-   T parting plane-   R rotation axis-   d_(A4) external diameter of the working chamber-   d_(A2) external diameter of the primary impeller-   d_(I5) internal diameter of the baffle plate-   d_(I4) internal diameter of the working chamber-   d_(A8) external diameter of the blade carrying part-   d_(A5) external diameter of the baffle plate-   p_(i7-2) internal diameter of the primary impeller in the region of    the radial external dimension-   d_(i5.2) internal diameter of the baffle plate

1. A hydrodynamic clutch comprising a primary impeller; a secondaryimpeller, which forms a working chamber with the primary impeller; and ameans for influencing a transmission ratio of the hydrodynamic clutch,comprising an element which forms an interference or baffle region,wherein said element is a ring-shaped disk or a washer segment thatextends at least partly into the working chamber and is displaceable inan axial direction in the working chamber.
 2. The hydrodynamic clutchaccording to claim 1, wherein the element is a ring shaped disk thatcomprises front sides, which point away from each other and are arrangedparallel to each other.
 3. The-hydrodynamic clutch according to claim 1,wherein the element that forms an interference or baffle region is aring shaped disk, and wherein a front side of the ring shaped diskelement, which points in between the impellers to a parting plane, isconstructed with an inclination over at least a part of its radialextension in a direction radial to a central diameter of the workingchamber.
 4. The hydrodynamic clutch according to claim 3, wherein thefront side of the ring shaped disk element, which points in between theimpellers to the parting plane, is constructed unevenly in a directionradial to the central diameter of the working chamber.
 5. A hydrodynamicclutch according to claim 4, wherein the front side, which points inbetween the impellers to the parting plane, is curved in the directionradial to a central diameter of the working chamber.
 6. The hydrodynamicclutch according to claim 1, wherein the element which forms aninterference or baffle region is arranged, viewed in a radial direction,in a region of an external diameter of the working chamber and comprisesan internal diameter that is larger than an internal diameter of theworking chamber.
 7. The hydrodynamic clutch according to claim 1,wherein the element which forms the interference or baffle region isarranged in a region of an internal diameter of the working chamber andcomprises an external diameter that is smaller than an external diameterof the working chamber.
 8. The hydrodynamic clutch according to claim 1,wherein the element is assigned to one of the two impellers, whereby theone of the two impellers comprises a blade carrying part, which containsa wall region that is displaceable in an axial direction and guides flowcirculation and wherein the element which forms the baffle andinterference region forms a structural unit with the wall region.
 9. Thehydrodynamic clutch according to claim 8, wherein the element whichforms the baffle or interference region forms an integral unit with thewall region.
 10. The hydrodynamic clutch according to claim 1, whereinthe element which forms the interference or baffle region is constructedas a separate component.
 11. The hydrodynamic clutch, according to claim10, wherein: the element which forms the interference or baffle regionis assigned to one of the two impellers; the one of the two impellerscontains a blade carrying part; the blade carrying part extends, viewedin a radial direction, always only over a part of an extension ofindividual blades of a blading in this direction; the blades of theblading freely project in a radial direction in a region of an internaldiameter or an external diameter of the working chamber in a region thatis free from the blade carrying part; and the element which forms theinterference or baffle region contains on an external circumference oran inner circumference guiding slits for guiding the blades of theblading which are arranged adjacent to each other in a circumferentialdirection.
 12. The hydrodynamic clutch, according to claim 10, wherein:the element which forms the interference or baffle region is assignedone of the impellers; the one of the impellers contains a blade carryingpart; and the blade carrying part and a blading, viewed in a radialdirection, include at an internal diameter or an external diameter ofthe one of the impellers, a constant diameter over an axial extension,whereby this is formed by shaping a blade part segment with a pertinentsub region of the blade carrying part.
 13. The hydrodynamic clutchaccording to claim 12, wherein the element which forms the interferenceor baffle region is guided by the impeller to which it is assigned, orby an element that is coupled torque proof to the assigned impeller. 14.The hydrodynamic clutch according to claim 10, wherein the element whichforms the interference or baffle region is guided by an element whichrotates relative to one of the impellers or by an element that iscoupled torque proof to one of the impellers.
 15. The hydrodynamicclutch according to claim 10, wherein the element which forms theinterference or baffle region is guided at a stationary component orcasing or by an element which is coupled torque proof to an impeller.16. The hydrodynamic clutch according to claim 1, wherein the elementwhich forms the interference or baffle region is assigned to the primaryimpeller.
 17. The hydrodynamic clutch according to claim 1, wherein theelement which forms the interference or baffle region is assigned to thesecondary impeller.
 18. A hydrodynamic clutch according to claim 1,wherein the means for influencing the transmission ratio of thehydrodynamic clutch includes a means for influencing a circulation flowin the working chamber.
 19. Procedure for influencing a torque that ahydrodynamic clutch can absorb comprising, providing the hydrodynamicclutch with a primary and a secondary impeller which together form aworking chamber; and providing the hydrodynamic clutch with at least anelement which forms a baffle or interference region for circulationflow, which extends at least partly into the working chamber, whereinthe element which forms the baffle or interference region is aring-shaped disk or washer segment that is displaceable in an axialdirection in the working chamber.
 20. Procedure according to claim 19,wherein the element which forms the baffle or interference region isactive at high slippage values in a region of a parting plane in theworking chamber and the influencing of the torque can be described as afunction of a position of the element that forms at least a baffle orinterference region.